#include "StdAfx.h"

#include <assert.h>

static unsigned long randseed = 1;

void srandom(unsigned long seed)
{
	randseed = seed;
}

/*
 * Pseudo-random number generator for randomizing the profiling clock,
 * and whatever else we might use it for.  The result is uniform on
 * [0, 2^31 - 1].
 */
unsigned long random()
{       
	long x, hi, lo, t;
	
	/*
	* Compute x[n + 1] = (7^5 * x[n]) mod (2^31 - 1).
	* From "Random number generators: good ones are hard to find",
	* Park and Miller, Communications of the ACM, vol. 31, no. 10,
	* October 1988, p. 1195.
	*/ 
	x = randseed;
	hi = x / 127773;
	lo = x % 127773; 
	t = 16807 * lo - 2836 * hi;
	if (t <= 0)
		t += 0x7fffffff;
	randseed = t;
	return (t);
}


float frandom(float flLow, float flHigh)
{
	float fl = float(random()) / float(2147483648.0f); // float in [0,1)
	return (fl * (flHigh - flLow)) + flLow; // float in [low,high)
}

long random_range(long from, long to)
{
	assert(from <= to);
	return ((random() % (to - from + 1)) + from);
}
